91 dies when hot
Thread Starter
Instructor
Joined: Jun 2006
Posts: 152
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From: louisville Kentucky
91 dies when hot
whats up guys,havent visited in a long time,
a friend of mine went to tennessee and broke down."hes a really good friend and went to tn. for chemotherapy-he has leukemia and hasnt worked in quite a while".anyway,im going down there to try and fix it.Im taking a fuel pump with me,what else do you think i should take with me and what else should i look for?this guy is really sick and this breakdown couldnt have been at a worse time.thanks in advance for any feedback,junior
a friend of mine went to tennessee and broke down."hes a really good friend and went to tn. for chemotherapy-he has leukemia and hasnt worked in quite a while".anyway,im going down there to try and fix it.Im taking a fuel pump with me,what else do you think i should take with me and what else should i look for?this guy is really sick and this breakdown couldnt have been at a worse time.thanks in advance for any feedback,junior
6th Gear
Joined: Oct 2007
Posts: 6
Likes: 0
I have a 91 vette. It ran fine when first started up. When it came up to temperature it started to miss. When I would pull up to a red light sometimes it would miss so bad it would totally shut down. It was usually hard to start after this. Other times I would pull up to a red light and have to put it in neutral and add gas just to keep it running. Engine would also surge 200 rpm at times.
Solution: I just finished putting 8 new fuel injectors in. Cured the problem. 91 vettes came stock with Multi-Tech injectors. Injector coils were open to fuel and additives which dissolved the wiring insulation thus shorting out the coils. This will cause the injectors not to fire if the coils are dead shorted. Take along an ohm meter and remove the electrical connectors to each injector and check the resistance of each coil. Should read 14-16 ohms. Any lower than that and the injector is going bad. A reading of 2 ohms or less indicates a shorted coil. Maybe this will help diagnose the problem. Search this site for posts by samlam. He has a good procedure for injector replacement. He's a great guy and will be a great help.
Best Wishes,
Barry C Jolly
Solution: I just finished putting 8 new fuel injectors in. Cured the problem. 91 vettes came stock with Multi-Tech injectors. Injector coils were open to fuel and additives which dissolved the wiring insulation thus shorting out the coils. This will cause the injectors not to fire if the coils are dead shorted. Take along an ohm meter and remove the electrical connectors to each injector and check the resistance of each coil. Should read 14-16 ohms. Any lower than that and the injector is going bad. A reading of 2 ohms or less indicates a shorted coil. Maybe this will help diagnose the problem. Search this site for posts by samlam. He has a good procedure for injector replacement. He's a great guy and will be a great help.
Best Wishes,
Barry C Jolly
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
fuel pressure tester will cut ''list of usual suspects'' in half...check for abt 40 psi with ign key on/engine off , with engine not turning over the ecm will only run the pump for 2 sec...pressure should bleed off slowly when key is turned off, hold 10 psi after 12 hour sit.
''hot quitter''...use a spare spark plug & plug wire to check spark output... i would also take along at least a known good distrib ign module, better a whole spare distrib.
''hot quitter''...use a spare spark plug & plug wire to check spark output... i would also take along at least a known good distrib ign module, better a whole spare distrib.
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Joined: Jun 2002
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From: Maryville Tn
CI 5 thru 12 Veteran
St. Jude Donor '09 thru '23
NCM Sinkhole Donor
I'd check the ignition module first before anything else. If the grease on the back of the module is gone, the module overheats. Good luck with getting the car back on the road. Stay safe.
Thread Starter
Instructor
Joined: Jun 2006
Posts: 152
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From: louisville Kentucky
I really appreciate the responses,thank you.
went to tn. this morning to diagnose the car but he was so weak I brought him back to a local hospital here in louisville.Ill go back next weekend for the car.the module was a good point.do gm's have problems with the pickup,hall effect switch like the fords do?
went to tn. this morning to diagnose the car but he was so weak I brought him back to a local hospital here in louisville.Ill go back next weekend for the car.the module was a good point.do gm's have problems with the pickup,hall effect switch like the fords do?
